Long-term intraocular pressure control of eyes that developed encapsulated blebs following trabeculectomy

Abstract

Purpose: To evaluate the long-term intraocular pressure (IOP) control of eyes that developed an encapsulated bleb (EB) following trabeculectomy.

Methods: Between 1994 and 1995, 25 eyes developed EBs and were randomized to medical treatment or needling without adjunct antimetabolites. Among the 25 patients who developed an EB, 21 were followed for at least 6 months. A control group of 21 consecutive eyes, which underwent trabeculectomy during the same period and that did not develop EBs was retrospectively selected. Success was defined as IOP <21 mmHg with or without medications. Kaplan-Meier survival analysis was performed to compare the groups.

Results: Among the 21 eyes that developed EBs, 12 (57%) had undergone transconjunctival needling and nine (43%) had received medical treatment. Mean follow-ups were 30.0 +/- 14.0 months, 33.3 +/- 18.5 months, and 37.4 +/- 2.6 months for the needling, medical treatment, and control groups, respectively (P = 0.19). Kaplan-Meier survival curves demonstrated that the control group showed a significantly lower chance of failure than both the needling and the medical treatment groups (P < 0.0001).

Conclusion: Encapsulated blebs may be associated with an increased risk for surgical failure.